The present invention relates to apparatus for inhibiting the transmission of solar energy above a predetermined temperature range but permitting transmission of said energy transmission of said energy below the range.
To utilize solar energy for heating and other purposes, it is usually desirable that the solar energy be collected within a spatial volume, such as within a dwelling, solar collector or a greenhouse, and that the influx of solar energy be maximized. However, particularly with respect to dwellings, excessive influx of solar energy which would raise the temperature within the dwelling to a non-acceptable level is undesirable. Accordingly, when the temperature inside the dwelling or other type of collector reaches a certain level, it is advantageous to stop the influx of solar energy, but to maximize the influx of solar energy until that temperature level is reached.
At the present time, control over the influx of solar energy is achieved in a mechanical fashion by interposing a non-transmissive layer. This non-transmissive layer can consist simply of drapes, shades, venetian blinds, and the like, and where the utilization of solar energy is to be maximized, the operation of such devices is often mechanized, as illustrated in the patent to Telkes, U.S. Pat. No. 2,595,905. However, such mechanical devices are generally cumbersome, expensive and often unsightly, and the necessity of their use represents a severe impediment to the efficient utilization of solar energy, particularly for home heating.